Transformations in the treatment of early-stage breast cancer have shifted the therapeutic approach from a “stage-centered treatment algorithm” to a “tumor biology-centered treatment algorithm,” Priyanka Sharma, MD, Associate Professor of Medicine, University of Kansas School of Medicine, Kansas City, stated at the recent Best of ASCO meeting in Chicago. Dr. Sharma summarized advances in breast cancer treatment in the past 50 years as a prelude to the session she conducted on triple-negative breast cancer.

Key Advances

As an example of the more tumor-centered approach, Dr. Sharma pointed out that 50 years ago, the standard surgical treatment was radical mastectomy, including removal of the breast, pectoralis muscle, and regional lymph nodes. In contrast, the current standard is breast-conservation treatment with sentinel lymph node dissection, even moving toward omitting axillary lymph node dissection for some patients with node-positive disease.

Radiotherapy, used 50 years ago only for mastectomy in high-risk disease, has now been widely adopted for treating breast cancer, due to improved efficacy, decreased toxicity, and faster, more convenient treatment. Chemotherapy has evolved from regimens based on cyclophosphamide, methotrexate, and fluorouracil to those based on an anthracycline and taxane, and tumor biology–driven assays to omit chemotherapy in early-stage hormone-positive breast cancer are now routinely used in clinical practice.

Another major development was the use of adjuvant chemotherapy with trastuzumab (Herceptin) for HER2-positive breast cancer. In addition, endocrine treatments for women with hormone receptor–positive disease have decreased recurrence and increased survival.

 “Large randomized studies done by the cooperative groups have defined every therapeutic principle in treatment of early-stage breast cancer over the past 50 years,” Dr. ­Sharma noted.

Remaining Challenges

Many challenges remain, she added. They include reconciliation of discordant stage/biology findings, standardization of next-generation pathology, de-escalation of therapy in patients with good prognosis, staying on the lookout for other major breast cancer–predisposing genes, organization of clinical trials and definition of success keeping in mind intratumor and intertumor heterogeneity and determination of which aberrations are critical to target, especially for triple-negative breast cancer. ■